A gaseous hydrogen- and carbon-containing compound is decomposed and found to contain 79.85 % carbon and 20.15 % hydrogen by mass. The mass of 158 mL of the gas, measured at 556 mmHg and 25∘C , is 0.142 g. What is the molecular formula of the compound?

For the answer to the question above, I'll show the solution to my answers

moles C = 82.66 g/ 12.0111 g/mol=6.882 moles H = 17.34 g/ 1.008 g/mol=17.20

17.20/ 6.882 =2.5 => H 6.882 / 6.882 = 1 => C

to get whole numbers multiply by 2 C2H5 ( empirical formula Molar mass= 29.062 g/mol)

n =pV/RT = 0.732 x 0.158 L/ 0.08206 x 298 K= 0.00473 molar mass = 0.275/ 0.00473 =58.1 g/mol

58.1/ 29.062 = 2

multiply by two the empirical formula

C4H10

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.